The invention concerns a method for detecting a hormone or antihormone resistance in tumours. The invention is intended for use in medicine, biology and pharmaceutical industry.
Tumours in organs depending on hormones such as in the breast and ovaries are tumour diseases met most frequently in women in industrialized countries. Thus, in about 12% of the female population breast cancer is diagnosed, with the peak of sickening being between the 4.sup.th and 6.sup.th decade of life. 3.5% of women die of it (Harris et al., New England J Med 327: 319-328, 1992).
Depending on the stage at which breast cancer is diagnosed the chances of recovery are between 30 and 70%. As about 2/3 of the tumours detected have hormone receptors these patients are given hormone preparations as primary medication. They are to competitively displace the natural ligand (oestrogen) from the receptor, thus affecting the growth of the tumours caused by hormones. Tamoxifen, a non-steroidal antioestrogen, is most frequently used for treating mammary carcinomas with the adjuvant use to prevent the development of metastases, yet also the prophylactic use for patients with a family-connected risk (Harris et al., New England J Med 327: 473-480, 1992).
It is known that about only half of the hormone receptor-positive patients respond to a tamoxifen therapy. This raises questions relating to the principle action of antioestrogens which, for the time being, are still largely unclarified. Thus, Berthois et al. (Molecular and cellular Endocrinology 99: 259-268, 1994) described that the immune reactivity of oestroqen receptors to an antibody will increase if oestradiol or tamoxifen are added in a cytosole test. The authors discuss a change of conformation of the oestrogen receptor by an in vitro interaction with hormones and anti-hormones as a potential mechanism for an apparent increase of the positions for the epitope binding.
Though tamoxifen is comparatively well-tolerated also in long-term use its possible cancerogenic potential has been discussed recently (Williams et al., Eur J Cancer Prev 1: 386-387, 1992).